Signaling device



Maid] 28, 1939.

L. H. ALLEN SIGNALING' DEVICE Filed Sept. 19, 1936 A 7' TOR/VE VPatented Mar. 28, 1939 UNITED STATES PATENT OFFICE Bell TelephoneLaboratories, Incorporated,

New York, N. Y., a corporation of New York Application September 19,1936, Serial No. 101,569

8 Claims.

This invention relates t0 audible signals such as telephone signalslocated at subscribers stations and particularly to damping devices foruse with telephone ringers.

It is the object of this invention to provide a subdued audible ringingsignal at a location, such as a telephone subscribers station, whichincreases gradually in sound intensity until the signal is answered.

It is desirable, in accordance With the practice of telephone operatingcompanies, to provide the telephone subscriber With a ringing signal ofsuch sound intensity as to be readily heard by the subscriber whenlocated at a reasonably great distance from the signal device. Inobtaining this desideratum it has been found that the telephone ringersin present day usage emit a signal of such sound intensity as to bestartling to the subscriber when situated close to the signal or whenthe telephone is located in a small confined area such as a privateoffice. Devices, such as gong dampers or sound resonators, which havebeen developed heretofore to overcome the harshness of the telephonesignal have been found to render the signal inaudible to the subscriberlocated at a distance from the signal when a telephone call arrives atthe subscribers station.

In accordance with a feature of the present invention the objectionablecharacteristics of the present day telephone ringer are overcome byproviding a ringing signal of variable intensity which, during thebeginning of the ringing signal gives forth a subdued pleasant sound,the intensity of Which gradually increases until a signal of maximumintensity is obtained. More specically, the telephone ringer is normallydamped so that when first actuated it emits a subdued pleasant sound.Continued application of ringing current to the telephone line causesthe heating of a bimetallic heater element which functions to graduallylessen the damping of the signal and to ultimately render the signalundamped so that a variable signal, ranging from a soft pleasant soundto a clear undamped audible signal, is obtained.

Another feature of the invention resides in connecting the heaterelement in circuit relation With the telephone line so that the ringingcurrent is utilized both to actuate the signal and to control thedamping device.

These and other features of the invention will be readily understoodfrom the following detailed description made with reference to theaccompanying drawing in which:

Fig. 1 is a side elevation of the ringer and damping mechanism and aschematic circuit representation illustrating one method of controllingthe damping device;

Fig. 1A is a fragmentary circuit representation illustrating amodication of the control method shown in Fig. 1; and

Fig. 2 is a representation similar to that shown in Fig. 1 and in whicha further modification of the control method is shown.

In Fig. 1 there is shown a Well-known type of audible signal, such as atelephone ringer, comprising coils II), armature II, clapper I2, gongsI3, armature restoring spring I4, yoke piece I5, cross-bar I6 andmounting bracket I'I. These elements and the manner in which theycooperate to produce an operative ringer structure are Well known tothose skilled in the art so that a detailed description thereof isbelieved unnecessary.

The cross-bar I6 is extended to the right and given a bracket-likeformation so as to provide seats I8 and I9. Mounted on the seat I8, inany suitable manner, is a thermostatic element 20 consisting of twostrips of dissimilar metals, which when subjected to heat moves its freeend up- Wards. hinge 2| to Which a metal rod or strip 22 is secured insuch a position as to overhang the ringer gongs I3. On the underside ofthe strip 22 im- Secured to the seat I9 is a reed type mediately overthe ringer gongs, a pad 23 of felt or other similar material is securedin any suitable manner. A nut 24 carried on the strip 22 near its hingedend accommodates an adjusting screw 25, the free end of which is inengagement with the bimetallic strip 20 near its outer end.

The strip 22 and its associated felt pad 23 constitute a damper for thegongs I3. The screw 25 is normally adjusted to maintain the damper incontact with the gongs I3 when the bimetallic strip 20 is in its normalunheated condition with suilcient pressure to insure a subdued signaltone When the coils I Il of the ringer are energized and the clapper rodI2 actuated.

The ringer coils I Il are shown bridged across the line L, which may bea telephone line circuit. Also connected across the line L in parallelwith the ringer coils is a heater coil 26 which is wound around thethermostat 20. At 2l is shown a source of signaling current which, intelephone practice, is located at a central cfce and which is connectedto the line by an operator, in the case of a manual system, orautomatically in an automatic system, to cause the actuation of theringer at a subscribers station as a ringing signal.

Application of current from source 21 to the line L causes current totraverse the ringer coils Ill and the heater coil 26. The ringeraccordingly functions and due to the close association of the damper andgongs a subdued pleasant tone emanates from the gongs I3. As the currenttraverses the heater coil 26 the thermostat 2D heats up and causes agradual upward movement of the adjusting screw 25 which graduallyrelieves the pressure between the felt pad 23 and the gongs i3 causingthe sound intensity of the signal to increase gradually. Continuedheating o1" the thermostat ultimately causes the disengagement of thedamper from the gongs so that the ringer gives forth a clear undampedsignal of maximum sound intensity.

When the ringing current is cut oil from the line, either at the centraloce or as a consequence of the called subscriber removing the receiverfrom its switchhook, in accordance with Well-known practice, the coilsIl! and 2S are deenergized. The signal is accordingly silenced and asthe thermostat 20 cools and returns to its normal position the damperagain contacts the gongs The arrangement disclosed in Fig. 1A provides alocal source of energy 30 for heating the thermostat 2B. Application ofringing current to the line L from the source 21 causes the operation ofrelay 3l which, at its armature and front contacts connects the source3!) to the heater winding 2S. The source of current 3B may be eitheralternating current or direct current. A variable resistance 50 isincluded in series with the current source 30 in order to permit thesubscriber to readily adjust the time during which the gongs are damped.

Fig. 2 shows an arrangement for supplying a local supply of low voltagealternating current Il@ (or direct current) for the heater coil 26 undercontrol of an auxiliary contact 4l on the ringer mechanism. In thismodication, when ringing current from the source 21 causes the operationof the ringer, the armature Il, which is in contact with the upperspring 42 through the medium of stud 43, vibrates and causes the rapidrepeated closure of -contacts 4| which connects the source 40 to theheater coil 26. l

In each of the embodiments disclosed the ringing signal received at thesubscribers station is highly damped for a period of time depending onthe design of the bimetallic strip 2E! and its power supply. When enoughheat has been stored in the heater element, mechanical movement thereofremoves the damping mechanism and the signal increases in soundintensity until no damping at all is provided.

Though the invention is disclosed as particularly applicable to theaudible signaling devices employed at telephone subscribers stations, itis to be understood that it may be employed in any signaling systemutilizing an audible signaling device.

What is claimed is:

l. In combination, a line circuit, an audible signal associatedtherewith, damping means for said signal, and means responsive tosignaling current on said line for actuating said signal and forprogressively rendering the damping eiect of said damping meansineffective.

2. In combination, a line circuit, a source oi signaling current, aringer associated with said line and responsive to current from saidsource in producing an audible signal, damping means associated with thegongs of said ringer for controlling the sound intensity of the signalproduced by said ringer, and other means responsive to current from saidsource for progressively removing said damping means from said gongswhereby said ringer emits a sound signal of progressively varyingintensity.

3. In combination, a line circuit, a source of signaling current, aringer associated with said line and adapted to be actuated by currentfrom said source, a damping device normally tensioned against the gongsof said ringer, and means responsive to a prolonged application ofcurrent from said source to said line for gradually relieving thetension on said damping device and ultimately disengaging said dampingdevice from the gongs of said ringer.

4. In combination, a line circuit, a source of signaling current, aringer associated with said line having a clapper controlling armatureand a pair of gongs, said ringer operating in response to an applicationof current from said source to said line to cause the clapper to strikethe gongs thereof, damping means for the gongs of said ringer,thermostatic means controlling said damping means, a second source ofcurrent, and means controlled by the armature of said ringer forconnecting said second source of current to said thermostatic means-uponthe application of current from said rst source to said line toprogressively actuate said damping means.

5. In combination, a line circuit, a normally damped audible signalassociated therewith and operating upon the application of signalingcurrent thereto, and means responsive to signaling current on said linefor progressively diminishing the damped condition of said signal, saidmeans functioning automatically upon the cessation of signaling currenton said line to restore said signal to its normal damped condition.

6. In combination, a line circuit, a source of signaling current, aringer associated with said line, a damping device normally tensionedagainst the gongs of said ringer, and means responsive to theapplication of current from said source to said line for operating saidringer, and means also responsive to the application of current fromsaid source to said line for gradually relieving the tension on saiddamping device and ultimately disengaging said damping device from thegongs of said ringer, said means also functioning upon the cessation ofcurrent from said source to restore said damping device to its normalposition against the gongs of said ringer.

'7. In combination, a line circuit, a source of signaling current, anaudible signal associated with said line and adapted to be actuated bycurrent from said source, a damping device for said signal, athermostatic control for said damping device and means comprising aheater winding connected across said line responsive to the u

